In construction equipment, such as an articulated, rubber-tired loader, ventilation of the cab is important. The environment in which such equipment operates is often dusty and the temperature frequently is quite high, higher than even ambient air temperatures because of the close proximity of the cab to heat sources, such as the engine, hydraulic reservoir, and hydraulic components. Outside air is therefore desirable and the operator's efficiency can often be enhanced when he may choose to have access to outside air even though that air is unfiltered or to improve the flow of air powered through a filter into the inside of the cab. In the past, one way to provide such access was by means of a door having a fixed window wherein the entire door can be latched in an open position. Alternatively, a dust door having a fixed window was provided that could be latched in an open position. One problem encountered with either of these arrangements was the hinges of the open door being stressed excessively because they were the major, and often the only, support for the door when latched open; the excessive stresses being generated by shock loads resulting from the equipment traversing rough terrain. In addition, either arrangement, but particularly the full door, was often undesirable because the size of the door was determined by the available size, contour and shape of the surface against which the door was latched. On articulated loaders clearance between the cab on one frame section and components on the opposite frame section was insufficient during extreme turns to permit the door to be latched in an open position. Even if such clearance is sufficient, damage to the door, the cab, or other loader components is likely should the latch device fail to hold the door securely in a fully open position.
Another form of prior art is the horizontally sliding window. While this arrangement provides selective variation of the area opened, such a window is inherently limited in the availability of area which can be opened to the outside air. The reason for this limitation is that the movable portion must remain within the confines of the door per se and hence must overlap a fixed pane of glass. Consequently, the maximum area capable of being opened to outside air is one-half the door width.
It is, therefore, an object of this invention to provide a door for construction equipment, particularly for articulated loaders, which does not have to be opened to provide access to outside air, which is capable of selective variation in area open to the outside, and which can withstand the stresses imposed thereon.
It is also an object of this invention to provide such a door which is adaptable to, and which will work with, cabs having a portion of that side mounting the door angled from the vertical.
It is a further object of this invention to provide such a door which permits convenient sub-assembly of certain portions thereof and which can readily be connected into a complete assembly prior to mounting the door on its hinges.
It is a still further object of this invention to provide such a door with a sub-assembly containing glass windows which can readily be mounted in a door frame assembly so as to effectively isolate the sub-assembly from some of the vibrations resulting from operation of the equipment.
These and other objects of the present invention will be more readily apparent upon a perusal of the following description of a preferred embodiment and the accompanying drawings, wherein: